Various types of tests related to patient diagnosis and therapy can be performed by analysis assays of a sample of a patient's infections, bodily fluids or abscesses. Such patient samples are typically placed in sample vials, extracted from the vials, combined with various reagents in special reaction cuvettes or tubes, incubated, and analyzed to aid in treatment of the patient. In typical clinical chemical analyses, one or two assay reagents are added at separate times to a liquid sample having a known concentration, the sample-reagent combination is mixed and incubated. Interrogating measurements, turbidimetric or fluorometric or absorption readings or the like are made to ascertain end-point or rate values from which an amount of analyte may be determined using well-known calibration techniques.
Although various known clinical analyzers for chemical, immunochemical and biological testing of samples are available, analytical clinical technology is challenged by increasing needs for improved levels of analysis. Due to increasing pressures on clinical laboratories to reduce cost-per-reportable result, there continues to be a need for improvements in the overall cost performance of automated clinical analyzers. In particular, sample analysis continuously needs to be more cost effective in terms of reducing consumables or the cost thereof required for each and every reaction assay.
One contributor to reducing cost-per-reportable result is the ability to repeatedly perform reaction assays in reaction cuvettes that are washed or otherwise cleaned after a first reaction is completed and between subsequent reaction assays. What has been overlooked, however, in many such cleaning systems, is that washing techniques are not fully capable of restoring a cleaned used cuvette to the degree of cleanliness of an unused cuvette. Thus, reagent residues from a prior reaction assay may remain in a washed reaction cuvette. Certain highly sensitive assays may be caused to have inaccurate results if certain reagent residues from preceding reaction assays are present in a cleansed reaction cuvette. One solution is to simply use a new reaction cuvette for each new assay however this defeats the desire to obtain a lower cost-per-reportable result by advantageously washing and reusing reaction cuvettes.
U.S. Pat. No. 5,741,461 discloses a sample analysis system having means for judging in advance of sample addition whether any of a plurality of reaction cuvettes located between a cleaning position and the sample addition position should be cleaned when the analyzer starts to operate.
U.S. Pat. No. 5,679,309 discloses an automatic analyzing apparatus having first and second wash complement cuvettes positioned at a wash point when reactant is added at first and second reactant addition points to the target cuvette. Once the wash complements are determined, the analyzer compares the complements with the inventory of wash designated cuvettes. If the first wash complement is designated for wash, the controller indexes and parks the reaction carousel for reactant addition at the first addition point to the targeted cuvette while simultaneously and opportunistically washing of the first wash complement cuvette. If the first wash complement cuvette is not ready to be washed but the second wash complement cuvette is, the analyzer indexes and parks the reaction carousel for addition of reactant to the targeted cuvette at the second reactant addition point and simultaneously and opportunistically washing of the second wash complement cuvette. If neither of the first or second wash complement cuvettes are ready for wash, no washing occurs and the analyzer indexes and parks the targeted cuvette at the first reaction addition point and reactant is added.
U.S. Pat. No. 6,027,691 discloses a cuvette wash station probe supply and disposal assembly for alternatively (1) providing pressurized washing liquid from a source of washing liquid to the cuvette wash station probe for washing a cuvette disposed within the random access analyzing station at the cuvette washing site and (2) providing a negative pressure to the internal chamber of the cuvette wash station probe for removing waste liquids from a cuvette disposed within the random access analyzing station at the analyzing site and for transferring such waste liquids to a disposal site.
From this discussion of the art state in automated clinical analyzers, it may be seen that while has been considerable progress has been made toward increasing assay processing efficiency, there remains an unmet need for a method for cleansing and reusing a reaction cuvette in an analyzer without sacrificing assay quality. In particular, the present invention presents a method to operate a multi-stall wash station so as to selectively wash a cuvette if the assay next performed in the cuvette is determined to be a highly sensitive or “exceptional” assay.